Interactions between two vector solitons

Summary form only given. Photorefractive spatial screening solitons exist in biased photorefractive media where the incident beam modifies the index of refraction in such a way that the beam becomes the first guided mode of its own self-induced waveguide. A beam of a given intensity (in units of the equivalent dark irradiance or of the background illumination) self traps in a specified medium and forms a soliton only at a given applied field, as dictated by the so-called existence curve. A vector soliton, consisting of two mutually incoherent beams self traps in the same way as a single soliton with an intensity equal to the total intensity of the pair of beams. In this manner, one can generate vector (Manakov-like) solitons in any noninstantaneous nonlinear media. In photorefractives, the only distinction from pure Manakov solitons is the saturable nature of the photorefractive nonlinearity (recall in Manakov´s case the nonlinearity is Kerr-type). We study the interaction between two fully-independent vector solitons. Intuitively, when the two vector solitons approach each other in a self-focusing medium, their intensities add up, thus the index of refraction between them increases and attracts more light towards the center region between the solitons. This gives the perception of attraction between the solitons. In the experiments we use a SBN crystal.